#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>

typedef int BTDataType;
typedef struct BinaryTreeNode
{
	BTDataType data;
	struct BinaryTreeNode* left;
	struct BinaryTreeNode* right;
}BTNode;

int size = 0;
void TreeSize1(BTNode* root)
{
	if (root == NULL)
		return;

	++size;
	TreeSize1(root->left);
	TreeSize1(root->right);
}

void TreeSize2(BTNode* root, int* psize)
{
	if (root == NULL)
		return;

	++(*psize);
	TreeSize2(root->left, psize);
	TreeSize2(root->right, psize);
}

int TreeSize3(BTNode* root)
{
	return root == NULL ? 0 :
		TreeSize3(root->left)
		+ TreeSize3(root->right)
		+ 1;
}

int main()
{
	return 0;
}